One of the most prevalent joint problems is back pain, particularly in the “small of the back” or lumbosacral (L4-S1) region. In many cases, the pain severely limits a person's functional ability and quality of life. Such pain can result from a variety of spinal pathologies. Through disease or injury, the vertebral bodies, intervertebral discs, laminae, spinous process, articular processes, or facets of one or more spinal vertebrae can become damaged, such that the vertebrae no longer articulate or properly align with each other. This can result in an undesired anatomy, loss of mobility, and pain or discomfort. Duke University Medical Center researchers found that patients suffering from back pain in the United States consume more than $90 billion annually in health care expenses, with approximately $26 billion being directly attributable to treatment. Additionally, there is a substantial impact on the productivity of workers as a result of lost work days. Similar trends have also been observed in the United Kingdom and other countries.
As part of the diagnostic process of determining the cause of pain coming from a joint such as the lumbar spine, health care providers rely on an understanding of joint anatomy and mechanics when evaluating a subject's suspected joint problem and/or biomechanical performance issue. Currently available orthopedic diagnostic methods are capable of detecting a limited number of specific and treatable defects. These techniques include X-Rays, MRI, discography, and physical exams of the patient. In addition, spinal kinematic studies such as flexion/extension X-rays are used to specifically detect whether or not a joint has dysfunctional motion. These methods have become widely available and broadly adopted into the practice of treating joint problems and addressing joint performance issues.
U.S. Patent No. US 2004-0172145 A1 discloses a tilting table capable of some movement to keep an iso-center at a fixed position. U.S. Patent Publication No.: US 2006-0185091 A1 describes a multi-articulated tilting table which positions and supports a subject during examination and treatment. U.S. Pat. Publication No. US 2005-0259794 A1 to Breen discloses a device for controlling joint motion and minimizing the effects of muscle involvement in the joint motion being studied. See also U.S. Pat. No. 7,502,641. This device minimizes variability among joint motion measurements across wide populations of subjects. As a result, comparative analyses of such measurements can be performed to determine statistical differences between the motion of “normal” and “unhealthy” subjects which in turn can provide a basis for determining the statistical confidence with which any given subject could be considered “normal” or “unhealthy” based solely on joint motion measurements. US 2009/0099481 A1 to Deitz for Devices, Systems and Methods for Measuring and Evaluating the Motion and Function of Joints and Associated Muscles discloses an apparatus configured to cause and control joint motion of a patient.
New approaches that involve the use of patient positioning devices during imaging discussed above, coupled with the use of imaging modalities that afford for moving-video type images (such as fluoroscopy) and automated computer image processing, have created new clinical diagnostic capabilities. These capabilities include the ability to produce low variability, quantitative measurements of the relative motion between anatomical structures in mammals, and in particular the ability to measure inter-vertebral kinematics in live human subjects. These new capabilities have been validated in clinical studies to significantly outperform older methods, such as flexion/extension X-rays, in determining whether or not a human spine joint has dysfunctional motion. With the development of these new systems for assessing inter-vertebral kinematics, there arises the need for components to enable a number of clinical applications of this newly-available diagnostic data.
One need is for new ways of viewing this new type of kinematic data. Another need is for the ability to leverage this data to improve upon the tools that users have in providing therapy to patients. Yet another need is to be able to generate measurement system results for anatomy that is typically hard or impossible to image, such as anatomy that does not stay fixed in space during operation, such as a knee (as opposed to a lumbar spine, which can be easily imaged with a fixed imaging device).